Troubleshoot Electrical Systems Safer and Faster with New Tester: Part 1

For many years, electricians and technicians looking for a quick current reading have reached for an electrical tester, a per­sonal everyday tool seen in tool belts the world over. For example, with Fluke’s T5 you slide the open fork around a conductor and safely measure AC current up to 100 amps. No need to clamp the fork shut or break the circuit. This “open fork” technology saves time and is safer to use than test leads, but you would still require test leads to mea­sure voltage.

Now, Fluke engineers have developed and are patenting a new technology called FieldSense that improves on the open fork functionality by performing not only AC current but also AC voltage and frequency measurements. Voltage and cur­rent measurements can be made on one device at the same time, in real time.  

The new Fluke T6 Electri­cal Tester with FieldSense technology enables simultaneous voltage and current measurements without metallic contact, and is the first handheld test tool using this new patent-pending technology.

With the Fluke T6-600 and T6-1000 testers, electricians can

• be safer — measure voltage up to 1000V through the open fork without test leads or exposed conductors
• be faster — with no need to open panels or remove wire nuts, electricians can speed through troubleshooting
• be more efficient — simultaneously measure and display voltage and current on the T6-1000. The T6-1000 also measures resistance up to 100.0 kΩ
• be everywhere — with the widest open fork in the industry, the T6 testers measure 4/0 wires up with current up to 200 A

The testers are 1000 V CAT III, 600 V CAT IV safety rated (600V CAT III for the T6-600 model) and feature an easy to read display with a backlight.

Applications for the Fluke T6 electrical testers

General applications include:

• quickly checking if a circuit is live before starting work
• quickly measuring individual voltages (either AC using FieldSense or AC/DC using test leads and Auto Select)
• quickly measuring current through the open fork up to 200 A AC
• determining component resistances up to 100 kΩ
• checking circuit continuity

Residential applications include:

• quickly measuring loads on a branch circuit at a service panel
• quickly measuring the load side voltage of a circuit breaker or fuse
• map outlets to breakers

Industrial applications include:

• quickly check circuit loading at panelboards (including feeder cables, branch circuits, and neutrals) and the integrity of a grounding circuit
• feed circuits coming into motors (up to 200 amps)

A safer way to test voltage

Contacting electrical conductors with test leads or alligator clips requires metal-to-metal contact, which as any electrician or technician knows carries the potential for arc flash. FieldSense eliminates that step. Because the measurement tool and the voltage source under test are iso­lated, the person performing the test is safer from potential electrical shock. This is performed by means of galvanic isolation or separation, the principle that isolates functions of an electrical current to prevent current flow. FieldSense takes a measurement of voltage without voltage flowing through the meter. Instead, the Fluke instrument, such as the T6-1000, senses an electrical field in the open fork to make the measurement, a safer method.

The T6 testers now make it possible to take reliable true-rms measurements in crowded junction boxes or along conductors with inaccessible end points, saving time and minimizing potential errors. And since the measurement is performed through the cable’s insulation, you reduce exposure to metallic conductors. You also decrease the poten­tial for errors, or making contact with the wrong conductor.

However, while the Fluke T6 electrical testers improve the safety of taking electrical measurements, workers should still wear appropriate personal protective equipment (PPE). Electricians should still wear arc-rated clothing and protective equipment including gloves, safety glasses or goggles, hearing protection and leather footwear. In lower voltage areas, measurements can be taken wearing minimal PPE, including gloves and protective eyewear.

How FieldSense works

Fluke R&D teams developed the open-fork voltage sensing technology, which involves transducing and calculating a known signal to derive measurements for the source voltage, by designing the device to generate a reference signal of known amplitude and frequency. Then, when grounded, the resulting composite waveform is detected by an electronic sensor built into the tester. After amplification, processing, and digital calculations, voltage and frequency measurements are derived.

The next challenge was to combine these two different physical phenomena — magnetic field sensing and electrical field sensing — into one device. After months of prototyping and testing, the Fluke R&D team determined the optimal design so these two technologies could be paired together. The result is that for the first time, voltage and current can be measured and displayed at the same time.

Find out more: www.fluke.com/t6.

Watch for Part 2: How to Use the Fluke T6 Electrical Testers with FieldSense Technology in the October 3 issue of EIN.